Air Force News Service
Released: 20 Oct 1998
14th Air Force experts explain upcoming meteor storm
By Capt. Robyn Chumley, 21st Space Wing Public Affairs
VANDENBERG AIR FORCE BASE, Calif. (AFPN) -- When the much-anticipated
Leonids meteoroid storm strikes in mid-November, the Air Force will bank on
a handful of experts to have prepared for the difficulties the service's
space assets could face.
Experts like Capt. Bruce Bookout, who first watched Leonids' bright bolide
meteors brighten the nighttime sky while growing up in Florida. A
self-admitted astronomy junkie, Bookout jumped at the chance to work the
first Leonids meteoroid storm in 32 years.
"My first reaction was, 'Oh, jeez, we've got a thousand questions to
answer,'" he said of the initially mind-boggling task. Bookout, assigned to
the 21st Space Wing at Peterson Air Force Base, Colo., was the chief of
space surveillance analysis for the 21st Operations Support Squadron there.
His charter was to examine what would happen to the wing's ground-based
missile warning and space surveillance assets during the Leonids storm.
What are the Leonids?
It begins with the comet Temple-Tuttle -- a fairly "young" comet that is a
couple hundred thousand years old. Comets -- essentially dirty snowballs --
start spewing off ice and dust as they near the sun's heat, creating streams
of house-dust sized meteoroids behind them. The comet Temple-Tuttle is no
different, except that its 33-year-long elliptical orbit around the sun --
which takes it almost to Uranus -- leaves clouds of meteoroids right in the
Earth's annual orbital path.
This intersection with the comet's meteoroids produces a celestial fireworks
display -- an annual meteor shower that appears to the casual observer to
emanate from the constellation Leo. It's a fairly routine event, with these
dust particles producing a show much like the summertime Perseids. Ordinary,
that is, until the Earth's track around the sun crosses comet Temple-Tuttle's
tail just months after the comet blew past the sun, something that will
happen Nov. 17.
The result: The potential for one son-of-a-gun sandstorm in space for
satellites. Thirty-two years ago, the Leonids produced an estimated 150,000
meteoroids per hour. Researchers place this year's storm count at anywhere
from a stormy 10,000 per hour, to the relatively tame 200 per hour. In
comparison, an average shower -- Earth encounters about 12 of them a year --
tends to be benign, with only 10-15 meteoroids an hour.
But in 1966, there were only 100 active satellites in space; now there are
more than 500. With grains of sand averaging the diameter of a human hair
traveling at 43 miles per second, an impact on a satellite might put a hole
in it -- or, of more significance, create an electrostatic discharge that
could potentially cripple a satellite's electronics.
That's where Bookout and others like Capt. Joel McCray come into play. Two
years ago, McCray's commander sent him to a University of Western Ontario
conference led by noted Leonids expert, Peter Brown. He left the conference
cautiously concerned about what the 1998 or 1999 storms could do to the Air
Force's space assets.
For 18 months, the chief of the requirements element in the 55th Space
Weather Squadron, 50th Space Wing, Schriever AFB, Colo., immersed himself in
Leonids. McCray's early pivotal role was gathering experts from each Air
Force satellite system together to explore the storms potential.
As early research unfolded, anxiety amplified -- particularly anxiety with
the speed of those pencil-tip size particles. Meteoroids normally travel at
about 12 miles per second; but because of the relationship of the Earth's
orbit to Temple-Tuttle's orbit, Leonids meteoroids rocket past at the speed
of a 22-caliber bullet.
The collision causes a "plasma discharge," which is when a particle impact
creates an electrostatic discharge that gives a voltage spike on the
surface.
If an impact occurs; if the resulting impact causes a discharge; if the
discharge gets inside the satellite vs. escaping into the space environment;
if the path of that discharge hits an electrical component, then the result
could be a fried satellite. But that's a lot of "ifs."
Regardless of the uncertainty, the Air Force's Leonids Tiger Team -- a team
of space operations experts -- is considering and preparing for each
potential "worst-case" scenario, said Capt. David Hembroff, a space
environment operations officer at 14th Air Force, Vandenberg AFB, Calif.
To minimize the storm's damage, the Tiger Team determined a comprehensive
series of mitigation strategies to protect space assets and allow the Air
Force to continue its vital missions. These strategies include normal
precautions such as powering down unnecessary onboard electronics and
reducing a satellite's cross-section.
"Plan for the worst, hope for the best," Hembroff said of the Tiger Team's
approach.
Bookout likened it to classic military strategy. "We gathered intel on the
'enemy,' and prepared for the 'enemy,'" he said. "We could be preparing for
the biggest nothing -- but we will be fully prepared for something and hope
for nothing."
Before the storm, satellite anomaly resolution teams [SART] will stand by
to quickly resolve any problem that arises. A SART comprises a satellite
system's contractors, engineers and operations personnel, and it usually
forms to analyze what happened to a satellite after a problem occurs. Maj.
John Kress, operations officer with the 821st Space Group at Buckley Air
National Guard Base, Colo., expects to be part of a SART during the Nov. 17
storm.
Kress is the Tiger Team's Defense Support Program satellite expert. Though
he initially thought Leonids "a big deal," as his analysis increased his
pucker-factor with the storm decreased.
"Although there is such a difference in analysis, it all comes down to
probabilities," he said.
An unfortunate reality, Lt. Col. Doug Hine said of the probability factor.
"That's why we've done such a thorough analysis across-the-board with our
satellite systems, because you don't know exactly how things will play out,"
the chief of current operations for 14th AF said. "We have to be prepared
for every contingency."
While most of the key players on the Tiger Team were "subject matter
experts" already -- and astronomy hobbyists to boot -- Master Sgt. Terry
Rich joined the team with barely a surface understanding of the difference
between a meteoroid and a meteorite. A weather forecaster by trade, and 13
years of computer programming under his belt, Rich's role was to develop a
3-D computer modeling product to look at potential places a satellite could
be hit. His information helped satellite operators compile a 245-page
contingency plan.
Building that contingency plan was a tremendous learning curve for Rich,
noncommissioned officer in charge of the weapons and tactics flight for the
50th Operations Squadron at Schriever AFB.
"I knew nothing about Leonids before this," he said. "Now I'm considered one
of the 50th Space Wing's experts."
He found it fascinating from day one.
"Consider the speed (of the meteoroids) and the damage it can cause," he
said. "A grain of table salt could punch a hole in a satellite. It amazes me
that something that small and that light could do that kind of damage."
Bookout considers the Leonids storm "a good thing."
"The more we're out in space, the more we need to learn about this," he
said. "It will help us realize how many 'threats' in space will make it
tough to do our job. It's a learning process that we need to go through."
It is an important learning process because the Earth will cross comet
Temple-Tuttle's path again in 1999 and some predict next year's storm will
be worse than this year's.
"People can debate all day long about which year will be worse," Hembroff
said. "Let the scientists debate the scientists. We know the what and when
about the storm. We have to consider the worst-case scenario -- that we're
going to get hit -- then prepare for that, wait and see what happens."
Two years of work for this Tiger Team, and it all boils down to one
nail-biting day. The chance that one of the Air Force's satellites will be
hit Nov. 17 is relatively small, Hembroff said. "But the fact there is a
chance means we have to be prepared."